Satellite images tracked the catastrophic impact of Japan's magnitude-9.0 earthquake and tsunami on the Fukushima nuclear complex and other key sites, and now they're tracking the reconstruction.

To mark Sunday's anniversary of the disaster, DigitalGlobe is releasing pictures showing "before, during and after" views of the devastation. You can see the three views of Fukushima here — but you really should check out our interactive slideshow to get a better sense of the changes that have taken place over the past year at Fukushima and at the Port of Sendai, which was destroyed in the tsunami.

"I'm struck by the progress, by how efficient the Japanese have been in reconstructing their infrastructure," Steve Wood, vice president of DigitalGlobe's analysis center, told me today. "In less than a year they've been able to turn this port into an active, functioning component. That's significant, considering that a year ago there were shipping containers, fires and mud covering that entire area. ... And there are literally hundreds of examples of that up and down the coast."

In the hours, days and weeks after the March 11 quake, satellite operators funneled fresh imagery to disaster workers, relief groups, government agencies and private companies coping with the aftermath. "We saw everything from big industrial partners who wanted to see the status of their factories, to government agencies involved in the actual reconstruction," Wood said.

Japanese officials and the U.S. military used the images to figure out which places were best for setting up aid operations, while relief organizations scanned wide-scale maps to see which areas were most in need of help. In places where planes weren't allowed to fly, "we were effectively the only game in town" for that initial post-quake aerial imagery.

Today, satellite images provide an effective way to gauge how much progress is being made, through comparisons of the before-during-and-after views. "To communicate and explain that to people is really an important and powerful tool that I've seen evolve over the years," Wood said. Pictures from space were important in the aftermath of the 2004 Indian Ocean quake and tsunami, they're important for Japan, and they'll be important for current and future hotspots such as Syria.

During Japan's crisis, Wood's team at DigitalGlobe was working 24/7, and the weeks and months have sped by. "It's hard for me to believe it's been a year," Wood said. For some of us, Sunday's anniversary may seem like a turning point — but it's really just one more day in the timeline of Japan's reconstruction. These pictures remind us that the work is far from finished.

DigitalGlobe

A labeled version of the image from Feb. 2 shows the status of the four nuclear reactor buildings at the Fukushima plant.